A copartnership



. I. HEISER.

PROTECTIVE DEVICE FOR ELECTRICALLY HEATED UTENSILS.

APPLICATION FILED PEB. I3. |919.

Patented Dec. 2,1919.

-frnn srarns Paritair onirica.

CHARLES JOSEPH HEISER, OF LOS ANGFLES, CALIFPRNIA, ASSIGNOR TO PACIFIC MANUFACTURING AND ELEC@ A COPARTNERSIIIP.

PROTECTIVE BEVICE FR ELECTRICAL'.

Application le February 13, 19in.

VAngeles vand State of California, have invented a new and useful Protective Device for Electrically-Heated Utensils.

My invention relates to the control of an electric current by means of a lfuse oper-ated by the conduction of heat from an electric heating element to a fuse contained in a chamber immersed in a liquid.

The principal object of my invention is to provide a novel form of fuse controlling ali-electric circuit; which Ycircuit heats a liquid through the medium of an electric heating element; the heating element being immersed. in the liquid or in contact with the utensil containing the liquid.

The invention consists in the construction and novel combination and arrangement ot parts hereinafter `described as illustrated in the accompanying drawings and pointed out in the claims hereunto appended. It is not `intended vthat the invention be limited .to speciic shapes and arrangements of of applying the fuse from the lbottom oi the utensil;

Fig. 3, is a view of the fuse and chamber on an enlarged scale as compared to Figs. 1 and 2. Y

Fig. Ll, is a cross section ralong the line ref-AQ Fig. 3. v

Fig. 5, is a cross section along the line B-B, Fig. 3.

In the drawing 1 is a casing or vessel under normal conditions being entirely filled with va liquid, except for that portion occupied by the fuse chamber t and that portion Specification of Letters Patent.

@F5-LEY, ANGEL? S, CALIFCRNIA,

Patented Dec. 2, 1919.

senin No. waere.

which may be lled vby tl e heating element 2, the casing being entirely7 inclosed eX- cept for the openings 22 and 23,; which may be connected respectively to the top Aand bottom of a storage tank containing' a liquid, In the casino' is a heating element 2,

'above mentioned which may be of any desired shape, the only requirement being that the arrangement oi same be such that the end of the Vfuse chamber containing the fuse 5 may be applied in close proximity to saine. A 'small space may be left between the fuse chamber e and the heating element 2, or if desired the fuse chamber 1 may be in contact with the heating element 2, by a relatively small area ci the one ltouching the other.

Energy is supplied 'from the electric -circuit 5-6, the current passing through the conductor 5 to the terminal stud 7 and thence through the ele tric heating unit 2 to the stud 8; thence through the fuseV 5 inl the chamber to theterminal stud 9 and thence through the conductor 6 tothe other side or" the power circuit. v

The circuit in the fuse itselfis from the terminal lug 10, through the lead in conductor 11 to 'the dfuse 5; thence through the other lead-in-conductor 12 to the terminal lug 1S. rThe lead-in-conductors are substantially insulated from each other and from the tube 19 by the insulating material 15. The l'in-'sulating barr'er (16) projects down between 'the points of juncture of the fuse 5 and the lead-'in-conductors 11 and 12. A cap 17 lined with the insulating` material 18 is arranged 'to slip on the tube 19. The whole fuse mechanism slips in the chamber t from which it can readily be removed.

In the case ci Fig. 1, this removal is accomplished by removing the terminal stud wing nuts S and 9. rlhe terminal board 1&1 is provided as shown.

Two methods are shown in the drawings of applying 'the Juse chamber d to utensils. In Fig. 1 the fuse chamber d is inserted from the top of the utensil and in Fig. 2 the vfuse chamber 25 is shown inserted from the bottom of a utensil.

TWhile the above described fuse has various uses it is particularly useful in connection with the installation of electrical heating devices to existing forms of hot water tanks. '5 Fig. 1, is illustrative of such heating device in which the opening 22 may be connected to the top of a water tank and the opening 23 to the bottom of same; the water in the tank being heated by virtue of a circulationof water set up when the'heating element 2 is in operation, under which conditions hot water will flow from the opening 22 to the top of the tank and cold water to flow from the bottom of the tank to the opening 23. The water in both the tank and the casing is under whatever pressure exists in the water mains to which it is assumed the tank is connected.

It will be noted that if the heating elesuiiicient length of time and little or no water be drawn of from the tank a condition will arise where steam will form in the top of the vessel (l). 0n accountof the concentrated form of electric heating element usually employed the element will not operate for any considerable length of time under these dry conditions without serious damage resulting which means usually that the heating element will become destroyed.

It will be noted that under normal conditions the fuseecan not reach a temperature materiall in excess of the temperature of the liqui in which it is immersed.

Under the conditions set forth above, however, where, due to the formation of steam the water is forced down from the top of the element it will soon reach a point where 40 the top portion of the element and the entire fuse chamber is no longer surrounded by a liquid. Under these conditions there being no longer a liquid present to conduct away the heat generated in the heating element 2 the temperature of the heating element will rise to a point considerably in excess of the normal operating temperature. Due to the fact that the heatin element 2 and the fuse and the fuse cham er 4 are mounted in close promixity to each other this seat will become conducted from the heating element 2 to the fuse chamber 4 and thence to the fuse 5, which will then melt. The point at which this melting occurs can be determined by the kind of material used in the manufacture of the fuse 5.

As the fuse 5 is in series with the element 2 the melting of same opens the electric circuit and current ceases to flow.

In Fig. 2 I show another application of the heat fuse chamber 25 containing heat fuse 5. In this instance the fuse chamber ment 2 should be allowed to operate for a 25 in the utensil 3 is in thermal contact through a limited area with the heating element 24. It will be noted that this thermal contact may be accomplished in any desired manner. The consideration is that the conduction of heat through the area of contact between the element 24 and the fuse chamber 25 will not under normal operating conditions exceed materially the conduction of heat from the fuse chamber 25 to the liquid. In other words the temperature of the fuse chamber under normal operating conditions must not materially exceed the temperature of the liquid.

The operation of the heat fuse under the conditions which would apply if the level of the water receded materially below the tip of the element 24 will be the same as described heretofore in the case of Fig. 1, except that by virtue of a thermal contact existing between the fuse chamber 25 and the element 24 a more rapid conduction of heat would take place to the fuse 5 and it would operate quicker.

I have heretofore set forth in these specitications the manner of removing the fuse mechanism from the chamber 4. It will be noted that when this mechanism is removed the cap 17 is carried with it. After this entire mechanism is removed it will be noted that the cap 17 can in turn be removed from the tube 19, which leaves the fuse 5 exposed. Under this condition it will be noted that a. new fuse can readily be applied to the ends of the lead-in-conductors 11 and 12.

The fuse 5 may be attached to the leadin-conductors 11 and 12 by being sweated on same or by being crimped on same or in any convenient manner.

What I claim is:

1. In combination; walls formin a veesel; an electric heating element so p aced es. to heat a body of liquid insaid vessel; and a heat responsive device adapted to open the circuit of said heating element whenever the temperature of said heat responsive device exceeds a predetermined value; said device being so placed as to be normally immersed in said liquid in close proximity to said element.

2. In combination; Walls forming a. ves sel; an electric heating element so placed as to heat a body of liquid in said veel; and a heat responsive device adapted t0 open the circuit of said heating element whenever the temperature of said heat responsive device exceeds a predetermined value; said device being so placed as to be normally immersed in said liquid in close proximity to said element; said heating element and said heat responsive device bei so situated with relation to each other that 125 said heat responsive device is partially out of thermal Contact with said liquid Whenever any portion of said heating element is out of thermal contact with said liquid.

`3. In a Water heater a Containing ves- 5 Sel; an electric heating element; lead-in Conduetors forming part of the electric circuit and connected with the terminals of a fuse, said fuse being contained. in a chamber Which under normal operating Conditions is immersed in the Water contained in said Vessel; the points of juncture of said 00nductors with said fuse being` insulated from each other by means of an insulating barrier.

CHARLES JOSEPH HEISER. 

